AS PHANTOM said, if it is NVIDIA GRAPHIC CARD problem than you should do what you are told by PHANTOM. if you beleive WIN FAST is a spyware or you have some doubt of bieng attack by spyware than you should run an anti spyware program instead of antivirus. PANDA is an antivirus program, to remove WIN FAST or any sppyware you should use Super anti spyware or Spyware Doctor, or run malware bytes, anyone on of these good anti spwyare programs.
http://darfuns.com/download-malwarebytes/